There are things I really like about Trump and there are things that drive me crazy. Yesterday, in his very strange (some of the things that he said) trip to Puerto Rico, he pledged to wipe out Puerto Rico's debt. As a result, the Puerto Rican bond market plunged.
Trump is treating this like one of his past business deals that failed. He would use other people's money and when it didn't work out he would walk away from the deal leaving lenders holding the bag. The Puerto Rico bond market represents money that is owed to companies, individuals, retirement plans, etc. This reckless gun slinging is very dangerous for a world awash in debt.